Interference Modeling and Capacity Analysis for Microfluidic Molecular Communication Channels

The impact of the interference on the molecular communication (MC) between a transmitter and receiver pair which are connected through a microfluidic channel containing fluid flow is investigated. The interference modeling and the capacity analysis is performed based on the microfluidic channel geometry, the flow velocity, and the distance. During the analysis, time-scale of biological oscillators is specifically targeted, which is in the range of several minutes to a few hours. The signal-to-interference and noise ratio is shown to be constant with respect to the location of the interfering transmitter. The capacity of the MC link between the designated transmitter and the corresponding receiver is shown to be upper bounded by 1 bit/per channel use when exposed to a single interfering transmitter. For the multiple, i.e., N, transmitters, the decay of pairwise MC capacity is also studied as a factor of N. Finally, placement of the two transmitter and receiver pairs on the opposite sides of the microfluidic channel is studied. Three different microfluidic interference channel configurations, i.e., both-sided interference (microfluidic X channel), one-sided interference (microfluidic Z channel), and interference-free, are proposed based on the distance of the receiver from the interfering transmitter, microfluidic channel cross section, and the fluid flow velocity. For large-scale integration of chemical analysis systems on a microfluidic chip, the provided information-theoretic analysis and the capacity expressions for the MIC can be utilized to analyze the throughput of the chip, which can lead to improvement in efficiency and optimization of the design.